a. Field of the Invention
The instant invention relates to steerable catheters. In particular, the instant invention relates to a self-locking wire lock for use in coupling steering wires to steerable catheter actuators.
b. Background Art
Catheters are used for an ever growing number of procedures. To name just a few examples, catheters are used for diagnostic, therapeutic, and ablative procedures. Typically, the physician manipulates the catheter through the patient's vasculature to the intended site, such as a site within the patient's heart. The catheter typically carries one or more electrodes or other diagnostic or therapeutic devices, which may be used for ablation, diagnosis, or the like.
It is well known that, to facilitate manipulation of the catheter through the patient's vasculature to the intended site, portions of the catheter shaft, especially the distal regions thereof, may be made steerable. That is, the catheter may be manufactured such that the physician can deflect the distal end of the catheter as necessary and desired to negotiate the tortuous paths of the patient's vasculature en route to the target site. Often, steerability is achieved by installing one or more steering wires (sometimes referred to as “pull wires”) along the length of the catheter shaft. These steering wires are coupled to one or more actuators that the physician can utilize to selectively tension the wires, thereby deflecting the distal end of the catheter. An example of such a steerable catheter is disclosed and taught in U.S. Pat. No. 5,861,024 to Rashidi, the contents of which are incorporated herein by reference. Other steerable catheters are disclosed in U.S. Pat. Nos. 5,395,329 and 6,308,090, both of which are hereby incorporated by reference as though fully set forth herein.
A number of methods and devices exist for coupling the steering wires to the actuators. In some steerable catheters, the end of the wire is wrapped about a screw and frictionally held in place between the screw head and the actuator when the screw is tightened down. In other devices, the wire is first placed over a hole in the actuator, and a set device, such as a pin or set screw, is then placed into the hole such that the wire is pinched between the set device and the wall defining the hole. Alternatively, the wire may simply be tied to a feature on the actuator. Such methods, however, are cumbersome, especially if subsequent adjustments to the wire are necessary.